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SERVICE INSTRUCTIONS
For radios that require an open circuit when the microphone is
on-hook (such as many Ericsson/GE models), the hang-up logic
can be reversed by the following procedure.
1. Open the microphone case by removing three retaining
screws.
2. Carefully separate the case halves, taking care not to lose the
rubber pieces associated with the cartridge assembly.
WHT
W2
CARTRIDGE
SP1
86B434R
W1
GND
HANG-UP BUTTON
W3
C1
C2
120pF
.001µF
R2
R1
68K
10K
C7
.018µF
C5
C6
R3
.001µF
120pF
27K
3. Add the following components to the PC board assembly at
the locations indicated by the highlighted parts in the
dash-line parts in Figure 5 and photo in Figure 6.
•
NPN Transistor Q2 (Shure Part No. 86A350; Motorola
2N5210)
•
Resistor R5, 56 kΩ,
4. Unsolder and move the blue wire from W5 to W4.
W4
W5
W8
JUMPER
BLU
(INSTALLED)
SP2
86A434
3
Q1
2
86A350
C3
C4
1
120pF
.001µF
R6
51
R4
470
C8 +
10µF
CIRCUIT DIAGRAM
FIGURE 5
3
1
/
W (Shure Part No. 45LA563C)
4
J1
1
AUDIO OUT/DC BIAS
2
PTT HI
3
HANGUP
4
PTT LO
5
N/C
6
GND
BLK
YEL
W6
W7
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